import Foundation
import Combine

final class CreatorChannelHomeViewModel: ObservableObject {
    private let repository = CreatorChannelHomeRepository()
    private let userRepository = UserRepository()
    private var subscription = Set<AnyCancellable>()

    @Published var isLoading = false
    @Published var response: CreatorChannelHomeResponse?
    @Published var hasLoaded = false
    @Published var selectedTab: CreatorChannelHomeTab = .home
    @Published var isApiFailedPlaceholderVisible = false
    @Published var errorMessage = ""
    @Published var isShowPopup = false

    func fetchHome(creatorId: Int) {
        isLoading = true
        isApiFailedPlaceholderVisible = false

        repository.getHome(creatorId: creatorId)
            .sink { [weak self] result in
                guard let self else { return }

                switch result {
                case .finished:
                    DEBUG_LOG("finish")
                case .failure(let error):
                    ERROR_LOG(error.localizedDescription)
                    self.applyApiFailedPlaceholderState()
                }
            } receiveValue: { [weak self] response in
                guard let self else { return }

                do {
                    let jsonDecoder = JSONDecoder()
                    let decoded = try jsonDecoder.decode(ApiResponse<CreatorChannelHomeResponse>.self, from: response.data)

                    if let data = decoded.data, decoded.success {
                        self.response = data
                        self.selectedTab = .home
                        self.isApiFailedPlaceholderVisible = false
                    } else {
                        if let message = decoded.message {
                            ERROR_LOG(message)
                        }
                        self.applyApiFailedPlaceholderState()
                    }
                } catch {
                    ERROR_LOG(error.localizedDescription)
                    self.applyApiFailedPlaceholderState()
                }

                self.hasLoaded = true
                self.isLoading = false
            }
            .store(in: &subscription)
    }

    func follow(creatorId: Int, notify: Bool = true) {
        isLoading = true

        userRepository.creatorFollow(creatorId: creatorId, follow: true, notify: notify)
            .sink { [weak self] result in
                guard let self else { return }

                switch result {
                case .finished:
                    DEBUG_LOG("finish")
                case .failure(let error):
                    ERROR_LOG(error.localizedDescription)
                    self.isLoading = false
                }
            } receiveValue: { [weak self] response in
                guard let self else { return }

                do {
                    let jsonDecoder = JSONDecoder()
                    let decoded = try jsonDecoder.decode(ApiResponseWithoutData.self, from: response.data)

                    if decoded.success {
                        self.updateCreatorFollowState(isFollow: true, isNotify: notify)
                    } else {
                        self.errorMessage = decoded.message ?? I18n.Common.commonError
                        self.isShowPopup = true
                    }
                } catch {
                    ERROR_LOG(error.localizedDescription)
                    self.errorMessage = I18n.Common.commonError
                    self.isShowPopup = true
                }

                self.isLoading = false
            }
            .store(in: &subscription)
    }

    func unfollow(creatorId: Int) {
        isLoading = true

        userRepository.creatorUnFollow(creatorId: creatorId)
            .sink { [weak self] result in
                guard let self else { return }

                switch result {
                case .finished:
                    DEBUG_LOG("finish")
                case .failure(let error):
                    ERROR_LOG(error.localizedDescription)
                    self.isLoading = false
                }
            } receiveValue: { [weak self] response in
                guard let self else { return }

                do {
                    let jsonDecoder = JSONDecoder()
                    let decoded = try jsonDecoder.decode(ApiResponseWithoutData.self, from: response.data)

                    if decoded.success {
                        self.updateCreatorFollowState(isFollow: false, isNotify: false)
                    } else {
                        self.errorMessage = decoded.message ?? I18n.Common.commonError
                        self.isShowPopup = true
                    }
                } catch {
                    ERROR_LOG(error.localizedDescription)
                    self.errorMessage = I18n.Common.commonError
                    self.isShowPopup = true
                }

                self.isLoading = false
            }
            .store(in: &subscription)
    }

    private func applyApiFailedPlaceholderState() {
        response = nil
        isApiFailedPlaceholderVisible = true
        hasLoaded = true
        isLoading = false
    }

    private func updateCreatorFollowState(isFollow: Bool, isNotify: Bool) {
        response?.creator.isFollow = isFollow
        response?.creator.isNotify = isNotify
    }
}